The software package ScicosLab experimental modeling of communication system based on noise-like signals, designed for simultaneous transmission in one channel of useful and service information for remote control modes of wireless communication system, which serves to provide information exchange between the control server and the control objects.
Time, spectral diagrams and autocorrelation function of the signals transmitted in the communication channel of the simulated communication system were obtained. It is noted that the obtained qualitative indicators show that the transmitted signals are noise-like and have a continuous appearance in the time and spectral region. Autocorrelation function also confirms the above. Also from the time and spectral diagrams it is impossible to visually distinguish the transmitted useful signals, which are sequences of uniform rectangular pulses, which indicates their secrecy from an outside observer. On the basis of wavelet analysis, a scalogram of the signals transmitted in the communication channel of the simulated communication system was obtained. As can be clearly seen in the diagram – in the communication channel is transmitted two signals (a useful signal and a noise-like signal), although the time, spectral diagrams and autocorrelation function is practically not visible. Thus, with the help of wavelet analysis it was possible to identify two signals from one noise-like signal, which indicates the lack of secrecy of the communication system based on noise-like signals. To counteract the wavelet analysis of communication systems based on noise-like signals, in which several useful signals are transmitted simultaneously in one communication channel, it is necessary that the signals transmitted in the communication channel have scalograms close to the white noise scalogram, which is a classic approach for protected wireless security systems. This can be achieved in different ways, for example, to use as an expansion code signals obtained by chaotic signal generators.